Process for preparing halogenated compounds

ABSTRACT

Aryl chlorides are prepared by contacting at elevated temperatures phosgene, carbon tetrachloride or a mixture of phosphgene and carbon tetrachloride and an aryl sulfonic acid, an alkali or alkaline earth metal arylsulfonate or any arylsulfonyl chloride. For example 4,4&#39;&#39;-dichlorobiphenyl can be prepared by heating 4,4&#39;&#39;-biphenyldisulfonic acid with at least two moles of phosgene or carbon tetrachloride per mole of the disulfonic acid to 250*C.

United States Patent Charles Camien Cumbo Wilmington, Del.

June 6, 1968 Nov. 23, 1971 E. I. du Pont de Nemours and CompanyWilmington, Del.

Continuation-impart of application Ser. No. 677,768, Oct. 24, 1967, nowabandoned Continuationin-part of application Ser. No. 712,598, Mar. 13,1968, now abandoned. This application J one 6, 1968, Ser. No. 734,870

lnventor Appl. No. Filed Patented Assignee PROCESS FOR PREPARINGHALOGENATED COMPOUNDS 8 Claims, No Drawings u.s. c1 26016491513, 260/290111., 260/313.1, 260/332.5,

260/3 46.l R, 260/646, 260/649 R, 260/650 R 1111.01. ..C07c 25/04, C07C25/18 Field of Search 260/649, 649 DP, 650, 612, 290 l-lL, 313.1, 332.5,346.1,

OTHER REFERENCES Websters New lntemational Dictionary, Unabridged 2ndEd. 1940, Meriam Co., Springfield, Mass. p. 158

l-lackh' s Chemical Dictionary, McGraw-Hill, New York, 4thEd. l969,p.62. 7 7 W Primary Examiner-Howard T. Mars Attorney-Norbert F. ReinertABSTRACT: Aryl chlorides are prepared by contacting at elevatedtemperatures phosgene, carbon tetrachloride or a mixture of phosphgeneand carbon tetrachloride and an aryl sulfonic acid, an alkali oralkaline earth metal arylsulfonate or any arylsulfonyl chloride. Forexample 4,4'-dichlorobiphenyl can be prepared by heating4,4'-biphenyldisulfonic acid with at least two moles of phosgene orcarbon tetrachloride per mole of the disulfonic acid to 250C.

PROCESS FOR PREPARING HALOGENATED COMPOUNDS RELATED APPLICATIONS Thisapplication is a continuation-in-part of my copending applications Ser.No. 677,768, filed Oct. 24, 1967 now abandoned, and Ser. No. 712,598,filed Mar. 13, 1968 now abandoned.

BACKGROUND OF THE INVENTION This invention relates to the preparation ofaryl chlorides. Direct chlorination reactions are often nonselective inaromatic systems, giving somewhat random distribution of substitution bychlorine. Neither the number nor position of chlorine atoms introducedinto an aromatic system by direct chlorination can be readilycontrolled.

The inadequacies of direct chlorination as a method of producing arylchlorides have brought about attempts to utilize the more selectivesubstitution patterns of sulfonation reactions; in many instances anaromatic ring can be sulfonated with only minimal formation of undesiredisomers. However, known methods involving the displacement of sulfonicacid and sulfonyl chloride groups in aromatic systems with chlorineatoms have not been economically suitable for commercial utilization.Thionyl chloride has been used in one such method [Meyer Montash, 36,719 1915)], but this reaction gives only low yields or requires largeexcesses of thionyl chloride. It is also known to dissolve certain arylsulfonic acids in water and treat with a halogen to effect partialdisplacement of the sulfonic acid groups with halogen. This reaction,however, also provides only low yields and frequently results in directhalogenation at positions other than that occupied by the sulfonic acidgroup.

The process of this invention provides an economical method forconverting aryl sulfonic acids, alkali and alkaline earth metalarylsulfonates and arylsulfonyl chlorides to the corresponding arylchlorides; high yields are readily attainable and the product isessentially isomerically pure. The ability to obtain aryl chlorides ofhigh purity is a particularly surprising and important advantage of theprocess of this invention.

SUMMARY OF THE INVENTION In summary, this invention is directed to aprocess for preparing an aryl chloride comprising contacting at elevatedtemperatures phosgene, carbon tetrachloride or a mixture of phosgene andcarbon tetrachloride and an aryl sulfonic acid,

an alkali or alkaline earth metal arylsulfonate or an arylsulfonylchloride.

: I in a preferred embodiment of this invention, phosgene, car

bon tetrachloride or a mixture of phosgene and carbon tetrachloride iscontacted with 4,4-biphenyldisulfonic acid,

an alkali or alkaline earth metal 4,4'-biphenyldisulfonate or4,4-biphenyldisulfonyl chloride at elevated temperatures to obtain4,4'-dichlorobiphenyl. In the most preferred method of producing4,4-dichlorobiphenyl, 4,4'-biphenyldisulfonic acid and carbontetrachloride are contacted at a temperature of from 200 to 300 C.

It will be understood that by aryl sulfonic acids an arylsulfonylchlorides" is meant compounds containing one or more sulfonic acidgroups and/or sulfonyl chloride groups attached to an aromatic nucleus.Typical aryl sulfonic acids and arylsulfonyl chlorides include those ofthe aromatic hydrocarbons such as benzene; substituted benzenes such asalkylbenzenes, nitrobenzenes and halogenated benacnes; coupled benzenerings such as biphenyl and terphenyl; fused benzene A R-SOgX C001; -0RC1+ XC1+ C0: SO,

wherein R is an aryl group and X is hydrogen or an alkali or alkalineearth metal cation. Reaction (2) has been found to proceed at aconsiderably faster rate than reaction l and the aryl sulfonic acidshave been found to react more rapidly then the corresponding alkali andalkaline earth metal sulfonates. It also appears that reactions (1) and(2) proceed through the corresponding arylsulfonyl chloride according tothe following general t uationsz 2) A (c 0 C1,)

R--S 0, 0C1. 1180,01

If an arylsulfonyl chloride is utilizedas a starting material, thereactions differ considerably from reactions (1) and (2) above in thatessentially no phosgene or carbon tetrachloride is consumed. Thus, theoverall reactions which occur when an arylsulfonyl chloride is employedas a starting material can be represented by the foll vwirg equations:

R-s0,c1 cool, 3-01 0001, so,

(4) R-SOgCl 0C1; i R-Cl 0014 S0;

It has been discovered that if reaction (4) is conducted in the presenceof at least a catalytic quantity of phosgene, the reaction rate isappreciably faster than if carbon tetrachloride alone is employed. Thus.when an arylsulfonyl chloride is reacted with at least a stoichiometricamount of carbon tetrachloride in the presence of a catalytic amount ofphosgene the reaction can be represented by the following s s fi(COC1,)" denotes the use of a catalytic amount of phosgene. Referring toequation (2'), it will be seen that phosgene is produced during thefirst step in the reaction of carbon tetrachloride and an aryl sulfonicacid or sulfonate; the phosgene produced in turn increases the rate ofthe second step of (2 according to equation (5 Since carbontetrachloride is usually somewhat more expensive than phosgene, it willordinarily be more commercially attractive to employ the latter toproduce aryl chlorides from aryl sulfonic acids and arylsulfonates.However, the converse may be true if the phosgene produced during thecourse of reaction (2) can be conveniently utilized by the manufacturerin other processes, e.g. the production of carbamyl chlorides,isocyanates, chloroformates and carbonates.

It will be appreciated that if both phosgene and carbon tetrachlorideare present in a reaction mixture containing an aryl sulfonic acid,arylsulfonate or arylsulfonyl chloride, two or more of the reactionsdiscussed above can be expected to 5 proceed simultaneously, although atdifferent rates depending From the preceding discussion it will be seenthat when phosgene is reacted with aryl sulfonic acid or alkali oralkaline earth metal arylsulfonate one mole of phosgene per sulfonicacid equivalent is consumed. Since the reaction of an aryl sulfonic acidor arylsulfonate with carbon tetrachloride proceeds more rapidly thandoes the reaction with phosgene. essentially one mole of carbontetrachloride per sulfonic acid equivalent is consumed even thoughphosgehe is present as a by product. Although essentially no phosgene orcarbon tetrachloride is consumed when an arylsulfonyl chloride is usedas a starting material, at least one mole of phosgene or carbontetrachloride per sulfonic acid equivalent is preferably employed. Anarylsulfonyl chloride is most readily converted to the correspondingaryl chloride by contacting it with at least one mole of carbontetrachloride per sulfonic acid equivalent and a catalytic amount ofphosgene; use of at least one-tenth mole of phosgene per sulfonic acidin this embodiment is preferred. Because of the highly reactive natureof phosgene, carbon tetrachloride and the free radicals which areapparently present during the course of the reactions discussed above,it is ordinarily preferred to use excess carbon tetrachloride and/orphosgene, rather than extraneous solvents or suspending media, incarrying out the process of this invention. Thus, it is ordinarilypreferred to employ at least 1.25 moles, and most preferably at least1.5 moles, of phosgene or carbon tetrachloride per sulfonic acidequivalent in the arylsulfonic acid, arylsulfonate or arylsulfonylchloride.

The presence of water in the sulfonic acid, sulfonates or sulfonylchloride and in the solvent or suspending medium should be avoided sincewater will destroy an equivalent amount of phosgene, thereby reducingthe economics of the process. The sulfonic acid, sulfonate or sulfonylchloride should also be essentially free of sulfuric acid, i.e., notmore than 1 percent by weight, if optimum results are to be obtained.Commercially available phosgene is generally quite pure and does notrequire any special purification prior to use.

The process of this invention is preferably carried out at temperaturesof from 200 to 300 C., and most preferably at temperatures of from 230to 270 C. From about 0.1 to about 24 hours are ordinarily required forthe reaction to go to completion. The reaction is most convenientlycarried out in an autoclave under autogenous or higher pressures.Removal of any excess carbon tetrachloride and/or phosgene after coolingof the reaction mixture gives a good yield of high-purity product.

As will be apparent to those skilled in the art, the process of thisinvention can be carried out in either a batch or continuous manner.

The method of this invention is further illustrated by the followingspecific examples.

EXAMPLE 1 31.4 parts by weight of dry, sulfuric acid-free4,4-bi-phenyldisulfonic acid and 340 parts by weights of carbontetrachloride are charged into an autoclave having a volume of aboutthree times that of the reactants. The autoclave is sealed, heated to250 C. and maintained at that temperature for 7 hours. The autoclave isthen cooled to ambient temperature, excess gases are released, theautoclave is opened and the contents are removed.

The excess carbon tetrachloride is removed by distillation, leaving 21.1parts by weight of essentially pure 4,4- dichlorobiphenyl. The yield inhand is 95 percent of theoretical. The product is analyzed by infraredspectroscopy, N.M.R. and gas-liquid phase chromotography and is found tobe isomerically pure.

EXAMPLE 2 18.0 parts by weight of dry, sulfuric acid-free benzene sul-.fonic acid and 340 parts by weight of carbon tetrachloride are chargedinto an autoclave having a volume about three timesthat of thereactants. The autoclave is sealed, heated to 230 C. and maintained atthat temperature for 8 hours. The autoclave is then cooled to ambienttemperature, excess gases are released, the autoclave is opened and thecontents are removed. The excess carbon tetrachloride is removed bystripping and distillation of the residue gives monochlorobenzene.

EXAMPLE 3 EXAMPLE 4 23.4 parts by weight of dry, sulfuric acid-freebiphenyl-4- sulfonic acid and 340 parts by weight of carbontetrachloride are charged into an autoclave which is sealed, heated to250 C. and maintained at that temperature for 7 hours. The autoclave isthen cooled to ambient temperature, excess gases are released, theautoclave is opened and the contents are removed. The excess carbontetrachloride is removed by distillation to give 4-chlorobiphenyl.

EXAMPLE 5 35.8 parts by weight of disodium 4,4'-biphenyldisulfonate and340 parts by weight of carbon tetrachloride are charged into anautoclave having a volume about three times that of the reactants. Theautoclave is sealed, heated to 260 C. and maintained at that temperaturefor 7 hours. The autoclave is then cooled to ambient temperature, excessgases are released, the autoclave is opened and the contents areremoved. The excess carbon tetrachloride is removed by distillation.Analysis of the crude product shows it to be 4,4- dichlorobiphenyl. Theyield is almost quantitative based on the amount of suifonate saltreacted.

EXAMPLE 6-31 Example 1 is repeated substituting individually for the 4,4biphenyldisulfonic acid an equivalent amount of the sulfonic acids,sulfonates and sulfonyl chlorides indicated below. The

indicated products are obtained.

Sulionic acid, sulfonates and Ex. suifonyl chlorides Product 6.....l-naphthalenesulionic acid l-chloronaphthalene. 7. 1,3-bcnzenedisu1ionicacid 1,3dichlorobenzene.

,8. 1,3,5-benzenetrisu1ionic acid.... 1,3,6-trichlorobenzene. 9.1,5-naphthalenedisulionic acid..

. 1,5-dichloronaphthaiene l-anthracenesulfonic acid l-chioroanthracene.1,5-anthracenedisu1tonlc acid.. 1,5-dichioroanthracene.

1,8 anthracenedis onic acid... 1,8-dichior0anthracene. 13....Z-phenanthrenesul onic acid. Z-chlorophenanthrene. 14....3phenanthrenesulfonic acid 3-chlorophenanthrene.

16. 4-chior0benzenesulfonic aci 1,4- iichlorobenzcnc. 16.3-pyrenesu1ionic acid 17.... 2-fiuorenesulionic acid-.. Z-chiorofluorene18.... 4-methylbenzenesulfonic acid 4-chioroto1uenc. 19....3-nitrobenzenesuilonic acid..... 3-chioronitrobenzene. 20....4,4-oxydibenzenesuitonic acid Bis(4-chlorophcnyl)- ether. 21.... Calcium1-naphtha1enesu1ionate....... i-chloronsphthalene. 22...-Dipotassium1,3-banzenedisullonate-.. 1,3-dichiorobenzene. 23 LithiumZ-phenanthrenesulfonate.-... Z-chiorophenanthrenc. Z-pyrrolesufonic acid2 chloropyrrole.

. 2iuransulionic acid 2-chlorofuran.

2thiophenesu1ionic acid.. 2-ch1orothiophene. 3-pyridinesuiionic acid3-chloropyridine. 4,4-biphenyldisulionyl ch1oride....4,4'-dich1orobiphenyl. Benzenesulionyl chloride Chiorobenzene.Z-naphthalenesultonyl chloride Z-Chloronaphthalene. BiphenyH-sufonyichloride 4-ch1orobiphenyi.

EXAMPLE 32 31.4 parts by weight of dry, sulfuric acid-free4,4'-bi-phenyldisulfonic acid and 40 parts by weight of phosgene arecharged into an autoclave having a volume of about three times that ofthe reactants. The autoclave is sealed, heated to 250 C. and maintainedat that temperature for 7 hours. The autoclave is then cooled to ambienttemperature, excess gases are released, the autoclave is opened and thecontents are removed. The excess phosgene is removed by distillation togive a residue of 4,4-dichlorobiphenyl.

EXAMPLES 3 3-5 8 Example 32 is repeated substituting individually forthe 4,4'-biphenyldisulfonic acid an equivalent amount of the sulfonicacids, sulfonates and sulfonyl chlorides indicated below. The indicatedproducts are obtained.

Sulfonlc acid, sulionates and sulfonyl Ex. chlorides Productinaphthalenesulionic acid lehloronaphthalene.

l,3 benzenedisulionic acid. l,3-dichlorobenzene.1,3,5-benzenetrisulionic acid. 1,3,5-trichlorobenzene.

. 1,5-dichloronaphthalene.

l-chloroanthracene.

. 1,6-dichloroanthracene.

. 1,8-dichloroanthracene.

1,5-r1aphthalenedisultonic acid.. l-anthracenesulionic acid1,6-anthracer1edisulfonic acid. 1,8-arrthracenedist1lionic acid.

41.... 3-phenanthrenesulfouic acid.. 3-chlorophenanthrene.

42.... 4-chlorobenzenesu1fonic acid.. 1,4-dichlorobenzene.

43.... 3-pyrenesulfonic acid 3-chloropyrene.

44.... 2fluorenesulionic acid Z-chloroliuorene.

45. 4methylbenzenesulfonic acid 4-chlorotoluene.

46.... 3-nitrobenzenesullonic acld..... 3-chloronitrobenzene.

47 4,4-oxydibenzenesulionic acid Bisg-chlorophenyhe er.

48-... Calcium l-naphthalenesulfonate l-chloronaphthalene.

49. Dipotassium 1,3-benzenedisulfonate. 1,3-dichlorobenzene.

50.... Lithium 2-phenanthrenesulionate..... 2-chlorophenanthrene.

51.... 2-pyrrolesullonlc acid 2-chloropyrrole.

62.... 2-furansulf0nic acid... 2chlor0iuran.

53.... Z-thlophenesulionic acid.. 2 chlorothiophenc.

64.... B-pyridinesulionic acid 3-chloropyridine.

55 4,4'-biphenyldisulfonyl chloride. 4,4-dichlorobiphenyl.

56. Benzenesultonyl chloride Chlorobcnzene.

57. Z-naphthalenesulfonyl chloride. 2chloronaphthalene.

68. BiphenyH-sullonyl chloride 4-chlorobiphenyl.

EXAMPLE 5 9 35.0 parts by weight of dry 4,4'-biphenyldisulfonylchloride, 5 parts by weight of phosgene and 200 parts by weight ofcarbon tetrachloride are charged into an autoclave having a' volume ofabout three times that of the reactants. The autoclave is sealed, heatedto 250 C. and maintained at that temperature for 7 hours. The autoclaveis then cooled to ambient temperature, excess gases are released, theautoclave is opened and the contents are removed.

The carbon tetrachloride is removed by distillation, leaving 22.2 partsby weight of essentially pure 4,4'-dichlorobiphenyl. The yield in handis 99 percent of theoretical. The product is analyzed by infraredspectroscopy, N.M.R. and gas-liquid phase chromotography and is found tobe isomerically pure.

EXAMPLE 60 18.0 parts by weight of benzenesulfonyl chloride, 3 parts byweight of phosgene and 300 parts by weight of carbon tetrachloride arecharged into an autoclave having a volume about three times that of thereactants. The autoclave is sealed, heated to 230 C. and maintained atthat temperature for 14 hours. The autoclave is then cooled to ambienttemperature, excess gases are released, the autoclave is opened and thecontents are removed. The carbon tetrachloride is removed by strippingand distillation of the residue gives chlorobenzene.

EXAMPLE 6] 42.0 parts by weight of Z-naphthalenesulfonyl chloride, 5parts by weight of phosgene and 340 parts by weight of carbontetrachloride are charged into an autoclave having a volume about threetimes that of the reactants. The autoclave is sealed, heated to 270 C.and maintained at the temperature for 5 hours. The autoclave is thencooled to ambient temperature, excess gases are released, the autoclaveis opened and the contents are removed. The carbon tetrachloride isremoved by distillation to give a residue of 2 chloronaphthalene.

EXAMPLE 62 EXAMPLES 63-81 Example 59 is repeated substitutingindividually for the 4,4'-biphenyldisulfonyl chloride an equivalentamount of the sulfonyl chlorides indicated below using 0.1 mole ofphosgene per sulfonyl chloride equivalent. The indicated products areobtained.

Product l-chloronaphthalenc.

Sulionyl chloride lnaphthalenesulfonyl chloride 64- LBbenzenedisulionylchloride. 1.3-dichlorobenzene.

65. 1,3,5-benzenetrisulfonyl chloride..... 1,3,5-trichlorobenzene.

.. 1,5-napthalenedisullonyl chloride..... 1,5-dichloronaphthalenc.

. l-anthracenesulfonyl chloride l-chloroanthracene.

1,6-dichlor0anthracene.

68.1; 1,5-anthracenedisulionyl chloride. 1,8-dichloroanthracenc.

69. 1,8-anthracenedisulionyl chloride.

70. Z-phenanthrenesullonyl chloride... Z-chIorophcnanthrene.

7i. 3'phenanthrenesullonyl chloride 3-chlorophenanthrene.

72. 4-chlorobenzenesulfonyl chloride ll4-dichlorobenzenc.

73.... 3-pyrenesullonyl chloride.............. B-chloropyrenc.

74.... Z-fluorenesulionylchlorlde 2-chlorotluorenc.

75. 4-methylbenzenesullonyl chloride. 4-chlorotoluene.

76. 8-nitrobenzenesulfonyl chloride l-chloronitrobenzene.

77.... 4,4-oxybis(benzenesulionyl chloride).. Blsgi-chlorophenyll et er.

78. Z-pyrrolesulionyl chloride Z-chloropyrrole.

79. Z-luransulfonyl chlorlde 2-chloroluran. 80. 2-thiophenesullonylchloride. Z-chlorothiophcnc. 81. 3-pyridinesullonyl chloride3chloropyridlne.

What is claimed is:

l. A process for preparing a chloride of an aromatic compound selectedfrom the group consisting of aromatic hydrocarbons, alkyl substitutedaromatic hydrocarbons. halogen substituted aromatic hydrocarbons, nitrosubstituted aromatic hydrocarbons and phenoxy substituted aromatichydrocarbons, comprising contacting at a temperature of from 200 C. to300 C. and autogeneous pressure the sulfonic acid, alkali or alkalineearth metal sulfonate or sulfonyl chloride of said compound with atleast one mole of carbon tetrachloride per sulfonic acid equivalent.

2. The process of claim 1 when conducted at a temperature offrom 230 to270 C.

3. The process of claim 1 wherein said sulfonic acid is 4,4-biphenyldisulfonic acid.

4. The process of claim 3 when conducted at a temperature offrom 230 to270 C.

5. The process of claim 1 wherein a sulfonyl chloride of an aromaticcompound selected from the group consisting of arcmatic hydrocarbons,alkyl substituted aromatic hydrocarbons, halogen substituted aromatichydrocarbons, nitro substituted aromatic hydrocarbons and phenoxysubstituted aromatic hydrocarbons, and a mixture of at least l mole ofcarbon tetrachloride per sulfonic acid equivalent and from 0.1 to 0.3mole of phosgene per sulfonic acid equivalent are contacted at atemperature of from 200 to 300 C.

6. The process of claim 5 wherein said sulfonyl chloride is4,4-biphenyldisulfonyl chloride.

7. The process of claim 5 when conducted at a temperature of from 230 to300 C.

8. The process of claim 7 wherein said sulfonyl chloride is4,4-biphenyldisulfonyl chloride.

* i i i i

2. The process of claim 1 when conducted at a temperature of from 230*to 270* C.
 3. The process of claim 1 wherein said sulfonic acid is4,4''-biphenyldisulfonic acid.
 4. The process of claim 3 when conductedat a temperature of from 230* to 270* C.
 5. The process of claim 1wherein a sulfonyl chloride of an aromatic compound selected from thegroup consisting of aromatic hydrocarbons, alkyl substituted aromatichydrocarbons, halogen substituted aromatic hydrocarbons, nitrosubstituted aromatic hydrocarbons and phenoxy substituted aromatichydrocarbons, and a mixture of at least 1 mole of carbon tetrachlorideper sulfonic acid equivalent and from 0.1 to 0.3 mole of phosgene persulfonic acid equivalenT are contacted at a temperature of from 200* to300* C.
 6. The process of claim 5 wherein said sulfonyl chloride is 4,4''-biphenyldisulfonyl chloride.
 7. The process of claim 5 whenconducted at a temperature of from 230* to 270* C.
 8. The process ofclaim 7 wherein said sulfonyl chloride is 4, 4''-biphenyldisulfonylchloride.